Rasarnava 12.21

12.21

grāhyaṃ tatphalatailaṃ vā yantre pātālasaṃjñake
tena tailena deveśi rasaṃ saṃkocayedbudhaḥ //

Or the oil of its fruit should be extracted in the apparatus named Pātāla;
with that oil, O ruler of the gods, the wise man should contract mercury.